Improved sensitivity roll-off in dual reference, buffered spectral-domain optical coherence tomography.

Area of Science:

• Biomedical Optics
• Medical Imaging Technology

Background:

• Spectral-domain optical coherence tomography (SD-OCT) is a widely used imaging technique.
• A key limitation of SD-OCT is sensitivity roll-off, which restricts imaging depth and applicability in certain biomedical contexts.

Purpose of the Study:

• To extend the imaging range of SD-OCT systems.
• To enable high-quality imaging of large luminal organs, such as the gastrointestinal tract.

Main Methods:

• Development of an SD-OCT system operating at a 1300 nm center wavelength.
• Implementation of two delayed reference arms to mitigate sensitivity roll-off.
• Integration of an optical switch and fiber optic delay line for synchronized spectral acquisition.

Main Results:

• The system demonstrated a significant increase in sensitivity, approximately 14 dB at the edges of the ranging depth.
• Successful ex vivo imaging of swine colon and in vivo imaging of duodenum were achieved.
• Enhanced sensitivity was observed for samples up to ~6 mm from the zero delay point.

Conclusions:

• The proposed SD-OCT system effectively reduces sensitivity roll-off, extending imaging range.
• The system offers modest hardware requirements and compatibility with endoscopic helical scanning.
• This advancement holds promise for improved diagnostics and visualization in gastrointestinal imaging.